1. Field of the Invention
The present invention generally relates to arm-power assisted bicycle operation and, more particularly, to an arm-drive apparatus mountable to a bicycle for providing upper body exercise through assisting leg power driving the bicycle.
2. Description of the Prior Art
A conventional bicycle is typically designed to be operated by movement of the legs of a rider/operator rotating a pedal crankshaft that drives the rear wheel of the bicycle. Arms and hands of the operator are typically relegated to steering the front wheel of the bicycle via a set of bicycle handlebars. In order to accomplish a more complete bicycle exercise routine, some designs have sought to augment the conventional leg operated bicycle design with a mechanism for using the arms as well. However, most arm-drive designs have achieved mixed results with respect to adaptability and effectiveness when attached to conventional bicycles.
One recent approach to arm-power assisted operation is disclosed in U.S. Pat. No. 5,511,810 to Tong. It teaches a removable arm-drive apparatus that is powered by long pivoting levers that attach to the front frame of the bicycle via a T-shaped bracket. Operating above and in front of the handlebars, the pivoting forward and rearward motion of the long levers then transfers the arm movement to the pedals by way of long connecting rods. The design disclosed in U.S. Pat. No. 7,000,934 to Capek similarly uses long levers pivoting about a bracket fulcrum that transfer arm motion to the pedals using connecting rods, but the bracket is instead attached to the bicycle frame near the center of the upper frame tube. Additionally, Capek removes the bicycle handlebars from the steering tube and replaces them with a steering disk and steering links that allow the cyclist to steer by rotating the upper ends of the long arm levers. In U.S. Pat. No. 6,032,970, Porter pivots long lever arms similar to the prior art patents discussed above but the fulcrum in this design lies near the bottom center of the steerable front end fork. Consequently, when the oscillating lever arms are turned the bicycle steers as well. Alternately, the apparatus connecting rods may be removed and the lever arms rigidly fixed to the fork so that the tops of the lever arms become handlebars and the bicycle is steered in a normal fashion. Another approach attempted to work around the inherent difficulty of merging steering capability into an arm-drive apparatus by adding a cable steering mechanism. In U.S. Pat. No. 5,775,708 to Heath, the exercise vehicle disclosed uses an arm-drive mechanism attached rigidly to the frame that uses lever arms connected to pedal planks for propulsion, but uses a hand-operated cable assembly attached near the top of the lever arms to provide steerability.
Despite these prior art designs, several problems still remain in the field of arm-drive bicycle operation. First, the previous devices often comprise a large or unwieldy lever system that interferes with normal bicycle pedaling and steering operation. It would be more desirable to couple a smaller more ergonomic design with a device that can be easily retrofitted onto an existing bicycle. Moreover, these prior art designs do not appear to be easily attachable to a bicycle while leaving the existing steering system intact and also while providing an efficient and stable arm-driven mechanism for the rider.
Thus, a need still exists for an arm-drive apparatus that overcomes the drawbacks of these prior art patents.